Press control device



Feb. 19, 1963 M. C OHN 3,077,966

PRESS CONTROL DEVICE Filed Aug. 6, 1959 2 Sheets-Sheet 1 INVENTOR MAURICE COH ATTORNEYS Feb. 19, 1963 M. COHN 3,077,966

PRESS CONTROL DEVICE Filed Aug. 6, 1959 w 2 Sheets-Sheet 2 FIG.?

INVENTOR FIG-8 MAURICE COHN 4 MS W M ATTORNEYS United States Patent 3,9773% PRESS CONTRQL DEVECE Maurice Colin, South St., Siouth Qoventry, Conn. Fiied Aug. 6, 1959, gets. No. 832,067 19 Ciaims. ((11. 1 2-125) This invention relates to a device for controlling operation of a punch press or the like into which a strip of stock is fed.

There are many punch presses and generally similar machines which are adapted to operate substantially continuously without an attendant or operator, the ram and movable die of the press being reciprocated automatically while stock is fed thereto in the form of a strip. The strip may be fed from a spool or drum and its movement is intermittent. That is, the strip of stock is advanced while the dies of the press are separated whereby a new portion of the strip is placed between the dies for punching or forming when the dies are again engaged. Damage to the dies may well ensue and is often encountered if the stock is not fed properly or becomes jammed in the press, and the dies may be damaged by continuing operation of the press after the strip of stock is exhausted or if the strip breaks before the end thereof is reached.

it is the genera. object of this invention to provide a device which will automatically shut off the press to avoid damage in the event the stock being fed thereto is not being fed properly or if the end of the stock is reached.

it is an additional object of the invention to provide a press control device having the aforesaid characteristics and which will also operate to shut off the press automatically in the event the stock being fed thereto is of greater thickness than that for which the press is set to operate upon.

it is a further obiect of the invention to provide a press control device of the type mentioned and which is a selfcontained unit that can easily be moved from one press or machine to another to control the operation thereof and which can easily and quickly be connected for control of a press without requiring any substantial modification of the press.

The drawings show a preferred embodiment of the invention and such embodiment will be described, but it \Vil]. be understood that various changes may be made from the construction disclosed, and that the drawings and description are not to be construed as defining or limiting the scope of the invention, the claims forming a part of this specification being relied upon for that purpose.

Of the drawings:

PEG. 1 is a top plan view of a device provided in accordance with the present invention and which is adapted automatically to shut off operation of a punch press or the like in the event the feed thereto is interrupted or fails;

FIG. 2 is a front elevational view of the device with parts thereof shown in section to illustrate details;

FIG. 3 is a transverse sectional view through the device taken as indicated by the line 33 of FIG. 2;

PEG. 4 is another transverse sectional view through the device taken as indicated by the line 4-4 of FIG. 2;

FIG. 5 is a left-hand end view of the control device shown in the other figures of the drawings;

FIG. 6 is an end view similar to FIG. 5 but with the addition of means for sensing thickness of the stock be ing fed;

FIG. 7 is a top plan view of the left-hand end portion of the device shown in FIG. 6; and

FIG. 8 is a detail view of an adjustable shaft incorporated in the thickness sensing portion of the device.

Referring to FIGS. 1 and 2, it will be observed that the press shut off device provided in accordance with the present invention is a compact unit the elements of which are all mounted upon a substantially rectangular base plate 1d. Near-the right-hand end of the base plate 10 there is provided a motor mount 12 which comprises a vertically extending plate screwed or otherwise rigidly secured to the base plate 10. The motor mount 12 has a suitable opening therethrough to receive the extending shaft of a motor 14 which is secured to the plate 12 as by screws or the like in such position that the shaft of the motor extends longitudinally of the base plate It? and substantially horizontally. As will be observed in the drawings, the motor is mounted on the right-hand face of the vertical plate 12 and the motor shaft extends through the plate 12 and beyond the left-hand face thereof.

As will now be described, the motor 14 is used to continuously drive a cam follower in a defined path which in the preferred embodiment shown is a closed circular path. As will hereinafter be described, it is desirable under certain conditions to have the cam follower adapted to be moved in the closed path in advance of the motor drive therefor. To achieve this end, the cam follower and the motor drive shaft are not directly con nected and the connections between the two include a slip connector or slip drive which permits the rotation of the cam follower to take place in one direction only.

More specifically, a disk 16 is secured to the extending end of the motor shaft, the motor shaft extending into the disk not at its center but at a point preferably more than half the distance from the center to the periphery of the disk. At a point near the periphery of the disk, but diametrically opposed to the location of the motor shaft, a dowel pin 18 is secured to the disk to extend horizontally to the left thereof. The extending left-hand end of the pin 18 is received between the furcations of a bifurcated fork 24) having its base secured to the righthand face of a drive disk 22 which forms a part of the slip connection or one-way drive referred to above. The drive disk 22 has a central bore receiving a sleeve 24 which is pinned to the right-hand end portion of a longitudinally extending horizontal shaft 26 which is rotatably supported in a block 28 as upon anti-friction bearing units 30, 30, the block 28 being disposed vertically and rigidly connected to the base plate 19. The left-hand end of the shaft 26 extends well beyond the block 28 and it is the left-hand end which receives the cam follower as will be hereinafter described.

As will be observed from the drawings, the shaft 25 and the motor shaft are coaxial but spaced apart. However, the motor shaft is used to drive the shaft 26 by means of the connection therewith which includes the motor disk 16, the eccentric pin 18, the fork 2t} and the one-way drive disk 22. The direction of rotation is counterclockwise as viewed from the right-hand end of the device or as viewed in FIG. 3 to which reference will now be had to describe the one-way drive and slip connection.

As shown in FIG. 3, the one-way drive disk 22 has a plurality of sockets 32, 32 drilled therein in circumaxially spaced relationship, the sockets extending tangentially to and opening upon the sleeve 24 in the bore of the disk. A ball 34 is disposed in each socket 32 and is biased toward the inner end thereof as by a spring seated upon a screw threaded into the outer end of the socket, the spring and screw not being shown. It will be observed that the tangential direction of the sockets 32, 32 is such that as an attempt is made to rotate the drive disk 22 counterclockwise relative to the sleeve 24, the balls 34, 34 will abut the ends of the sockets 32, 32 and bind against the sleeve 24 so that it and the shaft 26 will have to be rotated counterclockwise with the disk 22. On the other hand, if an attempt is made to rotate the drive disk 22 clockwise as viewed in FIG. 3 or if the shaft 26 and sleeve 24 are rotated counterclockwise relative to the disk 22, the balls 34, 34 will ride outwardly in the sockets 32, 32 and permit of such relative movement between the drive disk 22 and the sleeve 24-. Therefore, it will be seen that the shaft 26 can be rotated counterclockwise in advance of the rotation given the drive disk 22 by the ated to shut off the press it is not meant that the power means for the press must necessarily be deenergized, For purposes of this specification, the press is considered to be shut off when some instrumentality is operated by the switch 46 to prevent relative movement and closing of the press dies.

In further accord with the present invention, the cam which displaces the cam follower to shut olf the press as drive motor 14. This is the slip connection between the motor 14 and the cam follower which is an important feature of the present invention.

The cam follower mentioned above includes a circular plate or disk 36 provided with a central bore for securing it to the left-hand end of the shaft 26 and it also includes a follower pin 38 secured in the disk 36 in spaced relationship to its center, the pin 38 projecting longitudinally to the left of the follower disk. When the shaft 26 is rotated as described above, the cam follower pin 38 is rotated in a closed circular path in a vertical transverse plane through the control device, the direction of follower rotation being counterclockwise as viewed from the right-hand end of the device.

In accordance with the present invention, a cam (to be described) is provided to displace the follower pin from its path toward the right as viewed in FIG. 2 and thereby also to shift the follower plate 36 toward the right. This movement of the cam follower is utilized to operate switch means to shut ofi the press or other machine with which the device of this invention is associated. A coil spring 40 surrounds the shaft 26 and is disposed between the follower plate 36 and the left-hand bearing unit in the block 28 to urge the cam follower toward the left and thus to maintain the follower pin 38 in the vertical plane wherein its path of movement takes place. To provide for longitudinal displacement of the cam follower, the follower plate 36 may have a splined connection with the left-hand end of the shaft 26 or it may be pinned thereto so that the follower and shaft 26 will shift longitudinally as a unit. This is the provision made in the embodiment shown, and it will be observed that there is a bow spring washer 42 disposed between the right-hand bearing unit 30 in the block 28 and the one-way drive disk 22 which urges the shaft and follower unit toward the right but with less force than the bias provided by the spring urging the said unit toward the left and into the plane of movement of the cam follower pm.

.When the cam follower is displaced toward the right in its path of movement by the cam means to be described, the follower plate 36 shifts the armature or operating plunger 44 of a switch indicated generally by the reference number 46. The switch 46 is secured to a plate 50 which is longitudinally adjustably connected to the frame post or block 28. Preferably, the switch 46 is a conventional single pole double throw switch which is connected to the power leads (not shown) for the motor i4 and which is also operatively connected to the press or other machine so as to control the power means therefor. For example, the switch 46 may be connected in the power circuit to an electric motor driven press so as to de-energize the press motor when the cam follower is displaced, or the switch may be connected in the power circuit to a solenoid which may be utilized to operate a control valve or some other control mechanism in the press. In any event, the control connections through the switch 46 are such as to shut off the press when the cam follower is displaced and, preferably, the switch 46 is also connected to the drive motor 14 of this device so that that motor will be deenergized upon displacement of the cam follower and coincident with shut down of the press or other machine. When it is said herein that the device of this invention is operdescribed above is driven by the stock being fed to the press or other machine, the stock in most cases being advanced intermittently, whereby the cam will be driven intermittently. As will now be described, the arrangement of the cam and its drive is such that there will be no displacement of the cam follower from the plane of its circular path as long as the stock is being fed properly to the press or other machine and as long as the strip or supply of stock is not broken or exhausted.

The said cam comprises a circular disk 52 which is centrally mounted upon the right-hand end portion (FIG. 2-) of a shaft 54 for rotation therewith. The said shaft is rotatable in a vertically disposed block 56 rigidly secured to the base plate 10, the shaft being rotatable in anti-friction bearing units 58, 58 disposed within the block. The shaft 54 extends longitudinally and in coaxial alignment with the motor shaft and with the shaft 26, and the left-hand end of the shaft 54 extends beyond the block 56 whereupon the stock feed responsive drive elements are located as will be described.

As will be observed from FIGS. 2 and 4, the right-hand face of the cam 52 is engaged by the end of the cam follower pin 38 to define the vertical plane for the path of movement thereof. That is, the cam follower pin 38 normally engages that part of the right-hand face of the cam 52 falling within the are or segment 66 shown in FIG. 4. When the follower pin 38 engages that portion of the face of the cam 52, it is not displaced from its normal closed path of movement. However, the righthand face of the cam 52 is provided with a sloping or tapered portion 62 which when engaged by the follower pin 33 displaces the cam follower unit toward the right in FIG. 2, the follower pin 33 then riding upon that portion of the right-hand face of the cam embraced by the arc or segment 64 in FIG. 4.

,As previously mentioned, the switch 46 is preferably connected with the motor 14 so as to de-energize it at the time the press or machine receiving the stock is shut off. This, of course, occurs when the cam follower pin 38 engages the segment 64 of the cam 52 so that there will be little, if any, relative movement between the cam follower and cam and so that the follower pin will not have to move across that segment. However, in the event the control device motor 14 is not connected with the switch 46 as preferred, or in the event the switch fails to shut off the motor 14, provision is made to prevent the follower pin from traversing the segment 64 and again passing into the segment 60 to re-start the press. That is,

a stop block 66 is secured to the right-hand face of the cam 52 to engage the follower pin 38 and prevent further relative movement thereof along the face of the cam. When the follower pin 38 engages the stop block 66, the cam will be rotated by the drive motor 14 while the switch 46 is still positioned to shut ofi the press or other machine.

While the device of this invention is adapted to be used in installations where the stock is fed continuously, it is expected that it will most often be applied to punch presses or the like where the stock will be fed intermittently. In intermittent feeding, the cam 52 will be rotated while the stock is being advanced, but it will be at rest while the stock is not being advanced. During the time that the cam is at rest, the continuously driven cam follower pin 38 will be rotated in a counterclockwise direction (FIG. 4) across the segment 60 of the right-hand face of the cam 52. That is, the cam follower pin 38 will approach the slope 62 and the segment 64. If the cam follower pin climbs the slope 62 onto the segment 64, the cam follower will be displaced and the press will be shut off, this being caused by failure of the stock to be advanced. However, if the stock is advanced properly, the cam 52 will be rotated counterclockwise (FIG. 4) so that the slope 62 will be moved away from the cam follower pin and will not engage it to shut off the press. More specifically, the cam follower pin may closely approach the sloped surface 62 while the stock it at rest, but when the stock is advanced, the cam is rotated to advance the surface 62 relative to the cam follower pin, the said follower pin being in continuous movement in its closed path.

In further accord with the present invention, means is provided to adjust for stock feed in various increments of length without adjusting the rate of motor drive for the cam follower and without adjusting the drive for the cam. That is, a substantial length of stock may be advanced to a press for one operation during which time the cam 52 would be rotated well in advance of the cam follower pin 38 to widely separate the slope 62 from the said pin. Without the means mentioned above, it would require a considerable period of time for the cam follower pin to approach the slope 62, more time than would be necessary for closing of the press dies. On the other hand, a relatively short length of stock may be fed to the press which would advance the cam 52 only a short distance relative to the cam follower which would permit the cam follower to closely approach the slope 62 during the relatively short interval of time required for the dies to close.

In order that the cam will not be advanced too far ahead of the cam follower in the feeding of a long strip of stock to the press, a segment shaped stop 68 is circumaxially adjustably secured to the periphery and right-hand face of the cam 52 as shown in FIG. 4. One edge 70 of the said stop defines the trailing edge of the cam segment 6% and is arranged to engage the cam follower pin 38 and carry it and the follower in a counterclockwise direction as the cam 52 is rotated counterclockwise with advancing movement of the stock. Thus, the sloped surface cannot be advanced ahead of the cam follower pin 3% more than is permitted by the stop 68. Therefore, although a large increment of stock is advanced to the press, the cam follower pin is not widely removed from the cam surface 62.

The slip connection in the drive between the motor 14 and the cam follower is important in the aforedescribed operation. That is, the one-way ball drive described previously permits the cam follower to be rotated in a counterclockwise direction (FIGS. 3 and 4) by the cam 52 in advance of the motor drive without causing advanced rotation of the motor drive shaft and possible damage to the motor 14.

As previously mentioned, the stock feed responsive means for rotating the shaft 54 and thus driving the cam 52 is secured to the left-hand end of the said shaft. This means comprises a drive roller 72. (FIGS. 1, 2 and 5) which is pinned to the left-hand end of the shaft so as to be engaged and rotated by stock moving toward the press, thus rotating the shaft and the cam. As will be observed in FIGS. 1 and 2, the drive roller 72 is spaced from the left-hand end of the frame block 56, a ratchet wheel '74 being interposed between the said roller and the left-hand bearing unit 58 in the block 56. The ratchet 74 is coaxially secured to the roller 72 for rotation therewith.

As observed in FIG. 5, the stock S is advanced from right to left in movement toward the press or other machine receiving and using it. The strip of stock is supported in engagement with the bottom of the periphery of the drive roller 72 by two rollers 76, 76 rotatable on horizontal axes and supported on pins projecting to the left (FIG. 1 and FIG. 2) from a pivoted arm '78. The rear end of the arm is pivotally supported at 80 to the lefthaud face of the frame block 56 so that the arm 78 is disposed below the ratchet wheel '74 and so that the stock supporting rollers 76, 76 are disposed below the cam driving roller '72. The free end portion of the pivoted arm '78 is biased upwardly by a tension spring 82 which is connected between a pin extending to the right of the said arm and a pin extending forwardly from the block 56. Thus, the rollers 76, '76 are kept in spring biased engagement with the bottom surface of the stock S to press it against the periphery of the drive roller '72 whereupon the drive roller 72 and the cam 52 will be rotated counterclockwise (FIG. 4) as the stock is pulled into the press or other machine using it.

The stock is maintained in a straight line path and lateral or transverse movement thereof is prevented by means of a pair of guide rollers 34, 84 which are rotatably supported on vertical axes to project upwardly from a frame bracket 86 secured to the base plate It and being of reversed C-shape as viewed in FIG. 5. At least one of the rollers as is horizontally adjustably secured to the bracket 8-6 so as to adjust the distance between the said guide rollers to accoi imodate strips of stock of various widths.

it will be observed, particularly in FIGS. 2 and 5, that the forward free end of the pivoted arm 78 extends forwardly of the frame bracket 86 through a slot 88 defined therein and further defined by a plate 9i secured to the righ-hand face of the same frame bracket. When inserting the stock S in the device and advancing it initially to the press or other machine, the arm 7% is pivoted downwardly against the force of the tension spring 82 and it is lodged in its down position by a latch member 92 which is pivotally connected to the front face of the frame bracket 56. Then, the stock is passed between the guide rollers 84, 84 which are relatively adjusted to accommodate its width and the stock is passed over the depressed supporting rollers 76, 7s and fed into the press or other machine. Thereafter, the latch 92 is pivoted to the side as shown in FIG. 2 and the arm 78 is permitted to swing upwardly under the bias of the tension spring 82. This forces the stock against the bottom of the periphery of the drive roller 72 so that further movement of the stock toward the press will cause rotation of the cam. if the stock fails to feed, the drive roller 72 will not be rotated and the cam 52 will not be rotated, thus permitting the cam follower pin 32% to engage the cam slope 62 shifting the cam follower toward the right (FIG. 2) and actuating the switch 46 to shut off the press and to shut off the motor 14 as previously described.

When the supply or strip of stock S has become exhausted and is pulled from beneath the drive roller 72 and away from the support rollers 75, '76, the arm 78 will be pivoted farther upwardly by the spring 32. This causes a pawl 94 carried by the said arm beneath the ratchet wheel 74 to engage the teeth of the said ratchet wheel and to prevent any further inadvertent rotation of the shaft 54 and the cam 52. That is, the cam 52 will immediately cease rotation and be locked in a rigid position permitting the cam follower pin 38 to engage the cam slope 62 and shut off the press and the drive motor 14 of this device as described. Therefore, the ratchet and pawl elements described above may hereinafter be referred to as brake means for the cam.

In some but not all presses and other machines using sheet metal stock or strip stock of any kind, it may be desirable to stop the machine in the event the stock being fed thereto is thicker than intended. The device of this invention as thus far described will stop the machine in the event the stock does not feed the required amount and is thus not feeding properly, or in the event the supply of stock being fed is exhausted or the strip breaks. In further accord with the present invention, means can be employed with the device as described to operate it to stop operation of the press or machine in the event the stock thickness becomes too great. Such means will now be described.

The members included in this device to sense the thickness of the stock being fed and to operate the device to shut off the press in the event of an undesirable increase in thickness include a pair of generally similar rolls, one being an upper roll 1% and the other a lower roll 102 which are arranged in substantially vertical alignment on horizontal axes so that the stock will pass therebetween. The shafts supporting the rolls ltliland 192 are secured in a vertical frame plate 104 which is rigidly mounted on the base plate 19, the shaft 106 for the roll 1% being pinned in the plate 164- and the shaft 1% for the lower roll 1112 being rotatably adjustably secured in the plate 1%. The said rolls are mounted on the peripheries of anti-friction bearing units which are rotatable about the extending left-hand ends of the said shaft. Thus, the rolls are free to rotate about their respective shafts, but only the lower roll 1-92 is freely rotatable while the upper roll 1th is permitted only very limited rotation. More specifically, the upper roll 19%) is secured near its periphery above the shaft 106, as by a pair of screws 110, 110, toan arm 112 which is generally horizontally disposed and having its right-hand or front end (FIG. 6) extending over the ratchet wheel 74-. The left-hand or rear end of the arm 112 is biased downwardly by a tension spring 114 "which is connected between a pair of pins, one of the pins extending into the arm 112 and the other pin extending into the frame plate 1M on the rear face thereof. The spring biased arm 112 tends to rotate the upper roll in a counterclockwise direction as viewed in FIG. 6, but rotation in this direction is limited by a pin 116 extending from the frame plate 194 to engage the arm 112.

Both of the rolls 100 and 102 are formed with a radially projecting peripheral bead 118, as best shown in FIG. 7, to engage the stock being advanced between the rolls in a line contact rather than in a surface-to-surface contact.

As previously mentioned, the strip of stock is advanced to the press between the rolls ltltl and 102, the roll Hi2 rotating with movement of the stock while the roll 106' does not rotate. In order to effect such relationship between the stock and the rolls, the vertical location of the lower roll N2 is adjusted. This is accomplished by rotatably adjusting the shaft 18$ in the plate 104, the details of the shaft being shown in FIG. 8.

The shaft 1653 supports the bearing for the roll 102 and thus the roll 102 on a reduced diameter portion 120' which is formed on an axis or center line eccentric with respect to the axis or center line of an enlarged diameter portion 122 which is rotatable within a suitable bore formed in the frame plate 104. The extending end of the shaft 158 is provided with a screw driver socket 124 for turning the shaft within the plate lit-'3. Such rotatable adjustment of the shaft within the plate 104 shifts the roll 102 upwardly or downwardly due to the eccentric relationship between the shaft portions 120 and 122. When the roll 102 has been adjusted by rotatable adjustment of the shaft 108 to the desired position, the shaft is secured in such position in the frame plate 104- by advancing a set screw into engagement therewith.

Obviously, the vertical adjustment of the roll 102 relative to the roll 1% adjusts the spacing therebetween so as to receive stock of known thickness. The adjustment should be such as to provide for free rotation of the roll 162 with movement of the stock without causing any rotation of the upper roll 100. Then, in the event that the thickness of the stock being fed increases from that for which the adjustment is made, the increased friction between the rolls and the stock will tend to cause the upper roll 190 to rotate in a clockwise direction as viewed in FIG. 6.

Such rotation of the upper roll 1% is, of course, se verely limited by its connection with the arm 112. However, the upper roll 1% will rotate clockwise (F16. 6) sufiiciently to swing the forward or right-hand end of the said arm downwardly. In such downward movement of the arm 112, a pawl 126 mounted therein will be brought into engagement with the teeth on the ratchet wheel 74 to stop rotation thereof and thus to stop rotation of the cam 52 which will thereby effect displacement of the cam follower and shut off the press or other machine.

It is important to observe that a flat 128 is provided on the surface of the upper roll 10% adjacent to but slightly counterclockwise of the point of engagement with that roll and the stock S. Thus, as the roll is rotated or pivoted clockwise (FIG. 6) by stock of unusual thickness, the flat 128 will be disposed over the stock in such clockwise rotation of the roll 100 to increase the spacing between it and the roll 162 and thereby permit the stock to continue to advance to the press until the press is shut off by operation of the device of this invention.

The thickness control means incorporated in this device has been described as operating the switch 46 through the cam and cam follower. However, it should be quite apparent that the arm 112 forming a part of the thickness control means can be utilized to engage directly a switch such as the switch 46 for the same purpose.

While this invention has been described with reference to a device used primarily to control and shut off a reciprocating punch press of the type which requires intermittent feed of the stock, it should be quite apparent that the invention and device described can be used with many other machines using strip stock or the like which is advanced to the machine continuously. When adapted for such use, it is only necessary to provide a drive roller 72 of such diameter that the cam 52 will be rotated by advance of the stock at at least the same rate of speed at which the cam follower is rotated by the motor 14. Then in the event of failure, the cam will stop and the cam follower will be displaced in the usual way to shut off the press and shut off the drive motor 14 of this device.

It should also be apparent that while emphasis has been placed upon ability of the device of this invention to stop press or machine operation in the event of failure of the stock to feed or in the event the strip of stock is exhausted, the device will also operate to shut off the press or machine if the average speed of the stock advance is reduced. Further, it should be understood that while the stock being fed has been referred to as a strip, it is not intended that this word should be limited in designationto fiat rectangular stock. The device will operate for stock being fed in any length and of any desired cross-sectional configuration. For example, it is contemplated that the device will find use in the control of machines using wire as the stock.

Further, the preferred embodiment of the invention shown and described is arranged so that the cam follower is rotated by the motor of this device and the cam is rotated or driven by the advancing stock. It should be understood that the cam and cam follower can be reversed within the scope of this invention and as set forth in the appended claims. In addition, the brake means which is arranged to engage the cam ratchet when the supply of stock is exhausted may also engage the ratchet and thereby stop operation of the press or other machine in the event the stock reduces in thickness below a critical point.

Further, the elements of FIGS. 6, 7 and 8 which operate the device to shut off the press if the stock thickness increases may also be employed to actuate the device in the event of increase of some other cross-sectional dimension, and a generally similar structure may be used to operate the device in the event the stock is reduced in thickness. That is, the stock S can be advanced into the dies between a pair of rolls like the rolls 1th) and 102 and with an arm and pawl 112 and 126 secured to the upper roll but spring biased to effect engagement between the pawl and the ratchet. The stock of desired thickness passing between the rolls and being-engaged by the upper roll will pivot the upper roll to a position wherein the awl will be held out of engagement with the ratchet in opposition to the biasing or spring force. Then, in the event that the thickness of the stock is reduced below the desired dimension, the upper roll will not be held in the aforesaid rotated position and the arm will pivot to engage the pawl with the ratchet and thereby stop operation of the press or other machine.

The invention claimed is:

l. A device for shuttin off a power driven press or the like, which press is fed by the advance of stock thereto, said device and comprising switch means operatively connectible with the power means of the press to shut off the press when actuated, switch actuating means including movable means engaging the stock so as to be moved a normal distance in one direction as a result of the normal advance of the stock, a follower element driven in said one direction and having means engageable with said movable means and adapted to be operated thereby to actuate said switch means when said movable means has been moved in said one direction less than the said normal distance.

2. A device for shutting off a power driven machine, which machine is fed stock by the advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising drive means capable of operation at a substantially constant speed, a first part connected with said drive means so as to be driven at a substantially constant speed in one direction, a second part movable adjacent to said first part, means connected with said second part and adapted to move the same a normal distance in said one direction responsive to the normal advance of the stock strip to avoid said first part catching up to and engaging said second part, but said first part being engageable with said second part if the second part is not moved its normal distance, and switch means operable upon engagement of th said parts as aforesaid to shut off the power means of the machine.

3. A device for shutting off a power driven machine, which machine is fed stock by the advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, drive means for moving the follower in a path, switch means operatively connectible with the power means of the machine and associated with the said cam follower so as to be operated by displacement thereof from said path to shut off the power means of the machine, a cam having a surface engageable by the said follower to displace the same from said path, and means moving the cam only responsive to the normal advance of the steel: strip to keep the said surface ahead of the driven cam follower and out of engagement therewith.

4. A device for shutting off a power driven reciprocating press or the like, which press is fed stock by the intermittent advance of a strip thereof and which has power means adapted to be controlle by switch means, the said device comprising a c n follower, drive means for continuously moving the follower in a circular path, switch means operatively connectible with the power means of the press and assoc ted with the said earn follower so as to be operated by displacement thereof from said path to shut off the power means of the press, a cam having a surface engageable by the said follower to cisplace the sarne from said path, and means moving the cam intermittently and only responsive to the intermittent normal advance of the stock strip to the said surrace ahead of the cam follower and out of engagement therewith.

5. A device for shutting off a power driven reciprocating press or the like, which press is fed stock by the intermittent advance of a strip thereof and which has power means adapted to be controlled by switch means, the said evice comprising a cam follower, a motor for continuously rotating the follower in a closed circular path,

means operatively connectible with the power means of the press and associated with the said follower so as to be operated by displacement thereof from said path to shut ofl the power means of the press, a cam having a surface engageable by the follower to displace the same from the path, and means rotating the cam responsive to normal advance of the stock strip to keep the said surface ahead of the follower and comprising a drive roller connected with the cam and frictionally engaging said strip.

6. A device for shut-ting oif a power driven machine, which machine is fed stock by the advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, means for moving the follower in a path, switch means operatively connectible with the power means of the machine and associated with the said cam follower so as to be operated by displacement thereof from said path to shut off the power means of the machine, a cam having a surface engageable by the follower to cause displacement thereof, cam driving means connected with the cam and engaging the stock strip to move the cam only responsive to the advance of the stock strip to keep the said surface ahead of the cam follower and out of engagement therewith, and brake means engageable with said cam driving means to stop movement thereof and of said cam when the stool: strip is exhausted, said brake means being normally held out of engagement with the cam drive means by the presence of the stock strip, but being biased toward engagement with the said cant driving means.

7. A device for shutting off a power driven reciprocating press or the like, which press is fed stock by the intermitterrt advance of a strip thereofand which has power means adapted to be controlled by switch means, the said device comprising a cam follower, means for continuously moving the follower in a closed path, switch means operativeiy connectible with the power means of the press and associated with the said cam follower so as to be operated by displacement thereof from said path to shut off the power means of the press, a cam having a surface engageable by the said follower to displace the same from said path, cam driving means connected with the cam and engaging the stock strip so as to move the cam only responsive to the intermittent advance of the stock strip to keep the said surface ahead of the cam follower and out of engagement therewith, and brake means for stopping movement of the cam when the stock strip is exhausted, said brake means including means biased toward engagement with the cam drive means to stop movement thereof and of the said cam, the said last mentioned means being normally held out of engagement with the cam drive means by the presence of the stock strip.

8. A device for shutting oil a power driven reciprocating press or the like, which press is fed stock by the inter mittent advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, a motor for continuously rotating the follower in a closed path, switch means operatively connectible with the power means of the press and associated with the said cam follower so as to be operated by displacement thereof from said path to shut off the power means of the press, a cam having a surface engageable by the follower to displace the same from the path, drive means for rotating the cam responsive to advance of the stock strip comprising a drive roller connected with the cam and frictionally engaging the strip, and brake means for stopping rotation of the cam when the stock strip is exhausted including a ratchet rotatable with the drive roller and cam, and a pawl normally held out of engagement with the ratchet by the stock strip but biased toward engagement therewith.

9. A device for shutting off a power driven reciprocating press or the like, which press is fed stock by the intermittent advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, means connected with the follower for continuously driving the same in a closed path, which connection is adapted for drive of the follower in one direction only and includes a slip connector permitting movement of the follower in advance of the drive therefor in said one direction, switch means operatively associated with the follower and connectible with the power means of the press to shut off the press by displacement of the follower from its path, a cam having a surface engageable by the follower to displace the same from its path, means moving the cam intermittently and only responsive to the intermittent advance of the strip to keep the said surface ahead of the follower and out of engagement therewith, and means adjustably secured to the cam to engage the follower during movement or" the cam to move the follower in advance of the drive therefor, the last mentioned means being provided for adjustment of the device to various increments of stock feed.

10. A device for shutting off a power driven reciprocating press or the like, which press is fed stock by the intermittent advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising an electric motor, a cam follower connected with the motor to be continuously rotated in a closed path, the motor-follower connections being adapted for drive of the follower in only one direction along the path and including a slip connection permitting movement of the follower in advance of the motor drive therefor in said one direction, switch means operatively connectible with the power means of the press and with the said motor and associated with the said cam follower so as to be operated by displacement thereof from the said path to tie-energize the motor and shut off the press, a cam having a surface engageable by the said follower to displace it from the path, means rotating the cam intermittently and only responsive to the intermittent advance of the stock strip to keep the said surface ahead of the follower and out of engagement therewith, and means adjustably secured to the cam to engage the follower during rotation of the cam to move the follower in advance of the motor drive therefor, the last mentioned means being provided for adjustment of the device to various increments of stock feed.

11. A device for shutting off a power driven reciprocating press or the like, which press is fed stock by the intermittent advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, means connected with the follower for continuously driving the same in a closed path which connection is adapted for drive of the follower in one direction only and includes a slip connector permitting movement of the follower in advance of the drive therefor in said one direction, switch means operatively associated with the follower and connectible with the power means of the press to shut off the press by displacement of the follower from its path, a cam having a surface engageable by the follower to displace the same from the path, drive means connected with the cam and engaging the stock strip to move the cam only responsive to the intermittent advance of the strip and thereby to keep the said surface ahead of the follower and out of engagement therewith, means adjustably secured to the cam to engage the follower during movement of the cam to move the follower in advance of the drive therefor, the last mentioned means being provided for adjustment of the device to various increments of stock feed, and brake means for stopping movement of the cam when the stock strip is exhausted, the said brake means comprising means biased toward engagement with the cam driving means to stop movement thereof and of the cam, the said last mentioned means being normally held out of engagement with the cam driving means by the stock strip.

12. A device for shutting 01f a power driven recipro- (rating press or the like, which press is fed stock by the intermittent advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, a motor for continuously rotating the follower in a closed path, the connection between the motor and the follower being adapted for rotation of the follower in one direction only and including a slip connector permitting movement of the follower in advance of the motor in said one direction, switch means operatively connectible with the power means of the press and associated with the said follower so as to be operated by displacement thereof from said path to shut off the power means of the press, a cam having a surface engageable by the follower to displace the same from the path, means rotating the cam responsive to advance of the stock strip to keep the said surface out of engagement with the follower and comprising a drive roller connected with the cam and frictionally engaging the strip, means adjustably secured to the cam to engage the follower during rotation of the cam to rotate the follower in advance of the motor, the last mentioned means being provided for adjustment of the device to various increments of stock feed, and brake means for stopping rotation of the cam when the stock strip is exhausted including a ratchet wheel rotatable with the drive roller and cam and also including a pawl normally held out of engagement with the ratchet wheel by the stock strip but being biased toward engagement therewith.

13. A device for shutting off a power driven machine, which machine is fed stock by the advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, means for moving the follower in a path, switch means operatively connectible with the power means of the machine and associated with the follower so as to be operated by displacement thereof from said path to shut off the power means of the machine, a cam having a surface engageable by the follower to displace the same from said path, drive means connected with the cam to move the same responsive to advance of the stock to keep the said surface out of engagement with the follower, and means sensing a dimension of the stock and operable to stop cam movement it the stock increases in said dimension, said dimension sensing means including a member adjacent the stock and rotatable only due to increase in said dimension thereof and also including means carried by said member and movable with rotation thereof to engage the cam drive means and stop cam movement.

14. A device for shutting off a power driven press or the like, which press is fed stock by the advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, means for continuously moving the follower in a closed path, switch means operatively connectible with the power means of the press and associated with the said cam follower so as to be operated by displacement thereof from said path to shut off the power means of the press, a cam having a surface engageable by the said follower to displace the same from said path, drive means connected with the cam to move the same responsive to advance of the stock to keep the said surface ahead of the follower and out of engagement therewith, and means sensing dimension of the stock and operable to stop cam movement if the stock changes in dimension, said dimension sensing means including means engaging the stock and movable thereby only due to change in dimension thereof and being adapted to engage the cam drive means and stop cam movement.

15. A device for shutting off a power driven machine, which machine is fed stock by the advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, means for moving the follower in a path, switch means operatively connectible with the power means of the machine and associated with the said cam follower so as to be operated by displacement thereof from said path to shut ed the power means of the machine, a cam having a surface engageable by the follower to cause displacement thereof, cam driving means connected with the cam and engaging the stock strip to move the cam only responsive to the advance of the stock strip to keep the said surface ahead of the cam follower and out of engagement therewith, and brake means engageable with said cam driving means to retard movement thereof and of said cam when the stock strip is exhausted, said brake means being normally held out of engagement with the cam drive means by the presence of an advancing stock strip of desired thickness, but being biased toward engagement with the said cam drive means so as to engage the same and retard movement thereof and of said cam when the stock being fed is less than the said desired thickness.

16. A device for shutting off a power driven press or the like, which press is fed stock by the advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, means for continuously moving the follower in a closed path, switch means operatively connectible with the power means of the press and associated with the said cam follower so as to be operated by displacement thereof from said path to shut off the power means of the press, a cam having a surface engageable by the said follower to displace the same from said path, drive means connected with the cam to move the same responsive to advance of the stock to keep the said surface ahead of the follower and out of engagement therewith, and means sensing dimension of the stock and operable to stop cam movement if the stock changes in dimension, said dimension sensing means including means engaging the stock and movable due to change in dimension thereof and being adapted to engage the cam drive means and stop cam movement.

17. A device for shutting off a power driven reciprocating press or the like, which press is fed stock by the intermittent advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising a cam follower, a motor for continuously rotating the follower in a closed path, switch means operatively connected with the power means of the press and associated with the said follower so as to be operated by displacement thereof from said path to shut off the power means of the press, a cam having a surface engageable by the follower to displace the same from the path, means for rotating the cam responsive to advance of the stock strip to keep the said surface out of engagement with the follower and comprising a drive roller connected with the cam and frictionally engaging the strip, and means sensing thickness of the stock and operable to stop cam rotation if the stock increases in thickness, said thickness sensing means including a pair of rolls engaging the stock on opposite sides thereof, one of which rolls is rotated by the stock and the other of which is rotated a limited amount only due to increased thickness of the stock, said thickness sensing means also including means carried by said other roll and movable with rotation thereof to engage the cam drive roller and stop cam rotation.

18. A device for shutting off a power driven press as set forth in claim 8 and including in addition thereto, means sensing thickness of the stock and operable to stop cam rotation if the stock increases in thickness, said thickness sensing means including a pair of rolls engaging the stock on opposite sides thereof, one of the rolls being continuously rotated by advance of the stock and the other of the rolls being rotatable only due to increased thickness thereof, said thickness sensing means also ineluding a pawl movable with said other roll to engage the said ratchet and stop rotation of the cam due to increased thickness.

19. A device for shutting off a power driven machine, which machine is fed stock by the advance of a strip thereof and which has power means adapted to be controlled by switch means, the said device comprising switch means connectible with the power means of the machine and means sensing a dimension of the stock and operable to actuate the switch means if the stock increases in the said dimension, said dimension sensing means including a movable member positioned normally in spaced relationship but nonetheless adjacent to the advancing stock strip, the said movable member being engageable by the advancing stock strip and movable thereby only upon increase in the said dimension of the said stock strip and said movable member being provided with means for actuating the switch means to stop operation of the machine when so moved by the advancing stock strip, means supporting said advancing stock strip adjacent said movable member, and means for adjusting the position of the said stock supporting means and thereby adjusting the spacing normally existing between said stock strip and said movable member.

References Cited in the file of this patent UNITED STATES PATENTS 749,036 Dexter et a1 J an. 5, 1904 1,186,188 Hely June 6, 1916 1,583,889 Lariviere May 11, 1926 1,928,156 Leland Sept. 26, 1933 1,938,720 Preble Dec. 12, 1933 2,083,936 Backhouse June 15, 1937 2,209,155 Fagg July 23, 1940 2,433,120 Harrold Dec. 23, 1947 

1. A DEVICE FOR SHUTTING OFF A POWER DRIVEN PRESS OR THE LIKE, WHICH PRESS IS FED BY THE ADVANCE OF STOCK THERETO, SAID DEVICE AND COMPRISING SWITCH MEANS OPERATIVELY CONNECTIBLE WITH THE POWER MEANS OF THE PRESS TO SHUT OFF THE PRESS WHEN ACTUATED, SWITCH ACTUATING MEANS INCLUDING MOVABLE MEANS ENGAGING THE STOCK SO AS TO BE MOVED A NORMAL DISTANCE IN ONE DIRECTION AS A RESULT OF THE NORMAL ADVANCE OF THE STOCK, A FOLLOWER ELEMENT DRIVEN IN SAID ONE DIRECTION AND HAVING MEANS ENGAGEABLE WITH SAID MOVABLE MEANS AND ADAPTED TO BE OPERATED THEREBY TO ACTUATE SAID SWITCH MEANS WHEN SAID MOVABLE MEANS HAS BEEN MOVED IN SAID ONE DIRECTION LESS THAN THE SAID NORMAL DISTANCE.
 19. A DEVICE FOR SHUTTING OFF A POWER DRIVEN MACHINE, WHICH MACHINE IS FED STOCK BY THE ADVANCE OF A STRIP THEREOF AND WHICH HAS POWER MEANS ADAPTED TO BE CONTROLLED BY SWITCH MEANS, THE SAID DEVICE COMPRISING SWITCH MEANS CONNECTIBLE WITH THE POWER MEANS OF THE MACHINE AND MEANS SENSING A DIMENSION OF THE STOCK AND OPERABLE TO ACTUATE THE SWITCH MEANS IF THE STOCK INCREASES IN THE SAID DIMENSION, SAID DIMENSION SENSING MEANS INCLUDING A MOVABLE MEMBER POSITIONED NORMALLY IN SPACED RELATIONSHIP BUT NONETHELESS ADJACENT TO THE ADVANCING STOCK STRIP, THE SAID MOVABLE MEMBER BEING ENGAGEABLE BY THE ADVANCING STOCK STRIP AND MOVABLE THEREBY ONLY UPON INCREASE IN THE SAID DIMENSION OF THE SAID STOCK STRIP AND SAID MOVABLE MEMBER BEING PROVIDED WITH MEANS FOR ACTUATING THE SWITCH MEANS TO STOP OPERATION OF THE MACHINE WHEN SO MOVED BY THE ADVANCING STOCK STRIP, MEANS SUPPORTING SAID ADVANCING STOCK STRIP ADJACENT SAID MOVABLE MEMBER, AND MEANS FOR ADJUSTING THE POSITION OF THE SAID STOCK SUPPORTING MEANS AND THEREBY ADJUSTING THE SPACING NORMALLY EXISTING BETWEEN SAID STOCK STRIP AND SAID MOVABLE MEMBER. 